1. Field of the Invention
The present invention relates to a forceps suitable for moving a single lamina of semiconductor silicon wafer, and more particularly, to a vacuum-forceps for moving the semiconductor wafer while adsorbing it i.e. holding it against a surface of the forceps by utilising a vacuum and for separating the semiconductor silicon wafer by shutting off the vacuum in a desired position.
2. Description of the Prior Art
When processing semiconductor silicon wafers in the course of manufacturing an IC, it is often required to take a single wafer from a multiplicity of the laminated semiconductor silicon wafers for quality inspection or the like. The semiconductor wafer is in itself apt to be damaged. Such being the case, there has heretofore been proposed a vacuum-forceps with which the desired lamina of semiconductor silicon wafer lifted by vacuum adsorption.
In a conventional vacuum forceps, however, rust and corrosion are readily created on the working members of the forceps, which is attributed to the use of a variety of chemical agents for processing the semiconductor silicon wafers. This is likely not only to adversely affect the function of the forceps but also bring about a serious obstacle against the process of manufacture with the result that a good deal of rusty substances may be spread over the factory. In addition, the conventional vacuum-forceps is attended with such a disadvantage that, even if the adsorbing forces are shut off to separate the temporarily adsorbed semiconductor silicon wafer, the vacuum within the forceps does not disappear instantaneously, whereby the separation of the semiconductor silicon wafer is delayed. Furthermore, an adsorptive member of the prior art forceps is fixed in a given position and hence it is necessary that the manipulator changes his posture in accordance with a desired placement of the semiconductor silicon wafer. The conventional vacuum-forceps is simply arranged such that a tube connected to an air suction source is forcibly press-fitted in a rear nozzle of the vacuum-forceps so as to be joined thereto. It is therefore difficult to remove the tube for cleaning the vacuum-forceps after being used for a predetermined period of time, whereby the cleaning becomes impossible unless the separation is made by cutting the tube. In a conventional adsorptive member, a connection hole is formed in an adsorptive plate when joining a ventilation tube to the adsorptive plate; an external thread is formed at the tip end of the ventilation tube; and the two components are joined to each other by fitting this external thread in the connection hole. However, the connection hole is expanded in diameter when screwing the tip of the ventilation tube therein. Distortion due to this expansion in diameter causes roughness on the surface of the adsorptive plate, which undesirably hinders the adsorbing operation.
Accordingly, it is a primary obect of the present invention to provide a vacuum-forceps having its working members composed of non-corrosive fluorine contained resin.
According to one aspect of the invention, there is provided a vacuum-forceps suited to instantaneously separate the adsorbed semiconductor silicon wafer by virtue of an air-hammer phenomenon, the arrangment being such that a bypass is provided separately from vacuum suction passages within the body of the forceps, and the inside of the forceps communicates via the bypass with the atmosphere when shutting off the suction, thereby terminating the vacuum within the forceps.
According to another aspect of the invention, there is provided a vacuum forceps capable of adsorbing the semiconductor silicon wafer under any conditions, this forceps including: a spherical valve which is formed at a proximal end of the adsorptive member and is rotatably and swayably held at the tip of the forceps; and fastening means for fixing the spherical valve.
According to still another aspect of the invention, there is provided a vacuum-forceps which has a double-coupling consisting of a fixation joint screwed to the proximal end of the vacuum-forceps and of an attachable/detachable joint which is screwed to the fixation joint on its one side and is further connected to a suction tube on the other side thereof, this double-coupling permitting the suction tube to be easibly and surely attached to and detached from the body of the forceps.
According to a further aspect of the invention, there is provided a vacuum-forceps wherein a boss-like connection tube internally formed with a connection hole is provided on the wall of the proximal end of the adsorptive plate at the tip end of the adsorptive member, the tip of a ventilation tube is screwed in or press-fitted in the connection hole of the connection tube, and no distortion is created on the surface of the adsorptive plate even if the connection hole is expanded in diameter on account of the press-fitting process or screwing-in process.
According to an additional aspect of the invention, there is provided a vacuum-forceps, suitable for protecting the surface of the semiconductor silicon wafer, wherein at least a resilient impingement surface is formed on the adsorptive plate, and an adsorption ventilating groove is so formed therein as to encompass the resilient impingement surface in order to improve an adsorbing efficiency.
These and other objects, features and advantages of the invention will become more apparent on reading the following description of the preferred embodiments with reference to the accompanying drawings.